Recovery process



Dec. 14, 1943. I L, JONES 2,336,546

RECOVERY PROCESS Filed' May 25; 1941 FRESH FRESH GASOLINE FURFURAL ROSIN TO BE REFINED SOLUTION OF IMPURE ROSIN IN GASOLINE AL. 2

3 RAFFINATE EXTRACTION EXTRACT SOLUTION OF ROSIN COLOR 5 BODIES IN FURFURAL V SOLUTION OF PALE 4/ ROSIN IN GASOLINE PALE ROSIN1-8 EXTRACTION 9 RAFFINATE EXTRACT FURFURAL FURFURAI. SOLUTION OF RESIN OF INCREASED |i INSOLUBILITY IN GASOLINE s o1u"TI0 II IQMIMPURE ROSIN IN GASOLINE VAPOR RESIN OF INCREASED INSOLUBILITY IN GASOLINE FURFURAI; 4

In M Q.

Patented Dec. 14, 1943 UNITED RECOVERY PRGCESS .i'aenes L. Jones, Brunswick, Ga, assignor to Hercules Powder Company, Wilmington, DeL,

M a corporation of Delaware Application May 23, 1941, Serial No. 394,781

Claims.

This invention relates to a method of obtaining useful products from a resinous by-product produced in the refining of wood rosin.

Heretofore in the refining of crude wood rosin to obtain pale wood rosin, as for example in the selective solvent refining process shown in the U. S. Patent to Kaiser et al., 1,715,085, wherein a solution of crude wood rosin in gasoline is extracted with furfural which removes the rosin color bodies leavin-ga solution of pale Wood rosin in gasoline, evaporation of the furfural extract yields as a icy-product a very dark-colored resin. Disposition of this Joy-product has been a considerable problem because of its dark color and because it entails a loss of rosin since it contains asubstantial quantity of rosin. In the Kaiser et al. patent aforesaid it has been proposed to dissolve this by-product residue in gasoline and thereby extract the gasoline-soluble rosin therefrom. However, this proposal has not found favor in practice because the dark rosin thereby extracted is non-refinable by conventional rosin refining methods such as furiural extraction. I have discovered that the reason that this recovered resin is non-refinable is that when the furfural extract containing the dark resinous byproduct is evaporated to dryness, certain changes occur or decomposition products are formed which render the gasoline-soluble rosin material non-refinable.

It is an object of the present invention to recover a refinable rosin from the selective solvent extract referred to above.

Another object is to increase the yield of pale rosin obtainable with present selective solvent rosin refining processes.

Another object is to lower the gasoline-soluble content of the by-product resinous material referred to above.

Still other objects will more fully hereinafter appear.

I have discovered that if the extract containing the by-product resin referred to above and obtained by the selective solvent extraction of a light petroleum distillate solution of impure wood rosin with a selective solvent for color bodies therein which is capable of immiscibility with the light petroleum distillate and which may be typified by furfural, is extracted directly with a light petroleum distillate without evaporation of the selective solvent such as iurfural, there is obtained as the extract a petroleum distillate solution of a rosin which is capable of being refined by conventional rosin refining methods. extract may be evaporated to yield this rosin This which may be used as such or Which may subsequently be refined by any conventional method if desired. Alternatively, the extract itself may be refined by any desired method such as by means of a selective solvent capable of immiscibility therewith such as furfural. This refining-0f the extract may be performed by itself, 1. e., separately from any other refining to obtain a rosin which is likewise superior to ordinary rosin inrespects of crystallizing tendency and solubility and which may be used for example in core oil or the like. Or this refining of the extract may be effected by passing the extract into the original extraction zone where the solution of original crude rosin is extracted with a selective solvent such as furfural.

In a typical process of recovering rosin from, pine wood, the shredded wood is extracted with hot benzol, the drop liquor obtained being composed of benzol, crude terpene oils, and so-called N0. 3 rosin which is a mixture of gasolineinsoluble resin and FF rosin. This total resinous extract is evaporated to recover the benzol and then to distill off the crude terpene oils, leaving the No. 3 rosin. This No. 3 rosin is then dissolved in a mixture of furfural and gasoline in accordance with Hall 2,221,540 and layer separation effected. The bottom layer which is a solution of gasoline-insoluble pinewood resin in furfural is separated from the upper layer which is a gasoline solution of FF rosin. It is this gasoline solution which constitutes the original solution of crude rosin employed in a typical furfural or other selective solvent refining process, whereby there is obtained as the extract a furfural solution of the dark lay-product resinous material referred to above.

In accordance with the present invention, this selective solvent extract solution of rosin color bodies is extracted directly without evaporation with a light petroleum distillate such as gasoline which dissolves therefrom the rosin contained therein which would otherwise be lost in the byproduct resin.

This extraction may be accomplished in any' suitable manner. I prefer to carry it out by introducing the solution of by-product resin in selective solvent to the top of a suitable tower such as a tower packed with suitable contact media, such as 1" Berl saddles or a screen tower, introducing into the bottom of the tower a light petroleum distillate such as gasoline, and passing the gasoline and the solution of by-product rosin through the tower countercurrently to one another. The gasoline solution of rosin so obtained is removed at the top of the tower while the washed solution in furfural of by-product resin of increased insolubility in gasoline is removed at the bottom.

Conveniently, the gasoline solution of rosin thus obtained (the extract) is re-cycled to the original crude FF rosin gasoline solution being refined and refined together therewith in the manner of Kaiser et al., 1,715,085 above.

As the light petroleum distillate employed in carrying out the process of the present invention I may use any paraifin hydrocarbon or mixture of paraffin hydrocarbons boiling not above the boiling range of kerosene (which has an end boiling point not above 270 C.) and preferably essentially free from aromatic, naphthenic or olefin hydrocarbons. I prefer to use gasoline as the solvent, although butane, pentane, hexane, petroleum ether, V. M. & P. naphtha or any of various gasoline cuts may be used. It is preferred to use a normally liquid petroleum hydrocarbon. I may use what is known commercially as narrow range gasoline having a boiling point range of from about 200 F. to about 270 F. I prefer to use a distillate having an aniline point above 50 C. I may use system gasoline saturated With selective solvent. I use gasoline which is free from dissolved rosin or resinous material as the extractant.

I have found that the process may conveniently be carried out in conjunction with the usual refining operation of crude or impure wood rosin. In the accompanying drawing, there is shown a flow sheet diagram of such a combined process.

In accordance with the process represented in the drawing, the crude rosin and gasoline are commingled together to form a solution of impure rosin (block I). Alternatively, an already existing solution of the crude rosin in gasoline may be employed. This solution and furfural are commingled in any suitable extraction apparatus (block 3), and the phases are separated in the customary manner. The raflinate (block 4) comprises a solution of pale rosin in the gasoline. This is conveniently evaporated to yield a residue of pale rosin (block 8) and a distillate of gasoline saturated with furfural (block 'I) Conveniently, this recovered gasoline may be recycled for use in preparing the initial solution of impure rosin.

The extract phase from the initial extraction comprises a solution of the rosin color bodies in the furfural (block This solution may be considered as the starting material in the process of the present invention. This solution is extracted with gasoline (block 9), in any suitable manner as by the conventional countercurrent system. Conveniently, the gasoline employed for carrying out this extraction may be a portion or all of the gasoline recovered from the evaporation step employed to yield the pale rosin. The use of system gasoline which is saturated with furfural brings about an even better extraction. Thus, the gasoline of block I which is already saturated with furfural may advantageously be employed for carrying out the extraction of the furfural solution of the rosin color bodies (block 9). Following extraction or as a part of extraction, the gasoline phase and the furfural phase are separated. The gasoline phase (block I0) contains the gasoline-soluble portion of the rosin color bodies which is essentially an impure rosin. By recycling this solution of impure rosin in gasoline (block I0) and employing it in conjunction with the original solution of impure rosin in gasoline in the extraction step represented by block 3, a considerably higher yield of pale rosin may be effected.

The extract phase, namely the furfural solution of the substantially gasoline-insoluble pine wood resin (block II) is evaporated (block I2) to recover the furfural (block I4) and to leave as a residue a by-product resin of increased gasoline-insolubility (block I3) Desirably, the furfural (block I4) obtained by condensing the vapors from the evaporation step is recycled for use in the initial extraction of the impure rosin solution as indicated in the drawing.

A typical general procedure in accordance with the present invention comprises contacting one part of the furfural solution of the dark rosin color bodies (the resin Icy-product referred to above) and containing from 10 to by weight of the by-product resin, with from 1 to 8 parts by weight of gasoline in any type of countercurrent washing apparatus such as a packed tower, whereby there is obtained a gasoline extract containing from about 3% to about 20% by weight of furfural-refinable rosin and there is left as the raifinate a furfural solution of a resinous material of markedly increased gasolineinsolubility gasoline-insoluble raised by from 10% to as much as 50%, i. e., from 20 to to from 60 to While furfural is preferred as the selective solvent, in the extract solution, other selective solvents capable of immiscibility with light petroleum distillate may be used such as aniline,

phenol liquefied with water, furfuryl alcohol,

ethylene chlorohydrin, ethyl alcohol, methyl alcohol, methyl thiocyanate, methyl lactate, 2- nitro-l-propanol, liquid sulfur dioxide, etc.

The rosin dissolved in the extracting gasoline by the process of the present invention is refinable in the usual way either before evaporation of the gasoline or after evaporation of the gasoline followed by dissolution. This is true although the evaporation of the original furfural extract of dark rosin bodies followed by extraction of the solid resin or of the subsequently dissolved resin with gasoline yields a rosin which is not refinable by known refining methods such as furfural extraction.

Below are given several non-limiting specific examples of embodiments of the invention.

Emamples 1 to 9 A solution of rosin color bodies in furfural obtained by extracting a gasoline solution of FF wood rosin with furfural and containing 26.1% by weight of resinous material was washed once with gasoline, the mixture being heated to 0., agitated vigorously at this temperature for 10 minutes, cooled, allowed to undergo layer formation, and the gasoline phase separated and evaporated. The variables were the ratio of initial furfural solution to gasoline and the temperature to which the mixture was cooled prior to layer separation. These variables are indicated in the following table which also indicates the concentration of rosin in the separated gasoline phase and the yield of rosin. A one to three ratio gave best results and yielded a rosin of a G grade. Instead of evaporating the gasoline extract, it could be returned to the original extraction zone and extracted along with the FF rosin. The gasoline used for carrying out the washing step could be obtained by evaporation of the gasoline raifinate of pale rosin obtained in the original extraction which yielded the furfural solution.

A furfural solution of rosin color bodies obtained as the extract from furfural refining of a gasoline solution of FF wood rosin and containing 39.9% of resinous bodies was washed once with three times its weight of gasoline, the mixture being well shaken at an elevated temperature and the layers being separated at 25-30 C. The gasoline extract contained 3.7% of rosin and 5.9% of furfural.

The gasoline extract thus obtained was evaporated to leave a residue of rosin having the following properties: gradeequal to gum F, color-80 amber+25 red, gasoline-insoluble-- 0.11%, acid number142, saponification numberl64. A solution containing 20% of this rosin in gasoline was prepared and Washed with an equal weight of furfural, separation being efiected at 12 C. for one portion and at 3 C. for another portion. The gasoline solutions thus obtained were evaporated to yield a rosin of a color of H for the separation at 12 C. and a color of I for the separation at 3 C.

Example 11 A furfural extract of rosin color bodies contain ing 37.8% of resinous bodies was washed countercurrently four times with gasoline using a ratio of one part of furfural solution to two parts of gasoline. Washing and separation were at 80 F. The gasoline layer contained 8.14% of rosin (40.1% of the resinous bodies in the original furfural extract) analyzing: Lovibond-color 80 amber-t3? red, 0.18% gasoline-insoluble, melting point of 1'74.2 F. and an acid number of 156. The rosin color bodies in the original furfural extract contained 56.9% by weight of gasolineinsoluble and had a melting point of 189.8" F. while the resinous material left in the furfural phase after the washing contained 87.2% of gasoline-insoluble, had a melting point of 200.8 F. and amounted to 30.96% by weight of the washed furfural phase.

Example 12 Example 11 was duplicated exactly except that only two washes were given and that the ratio employed was four parts of gasoline to one part of furfural solution by weight. The gasoline extract contained 3.88% of rosin (39.9% by weight of the resinous bodies present in the initial furfural extract). This gasoline extract was evaporated to give a rosin analyzing; color FF, 80 amber+37 red, gasoline-insoluble 0.18%, melting point 167 F., and acid number 146. The washed furfural phase contained 31.1% of a resinous material having a melting point of 213.4 F. and gasoline-insoluble of 88.8%.

It will be understood that the details and examples hereinbefore set forth are illustrative only Qel and that the invention as broadly described and claimed is in no way limited thereby.

What I claim and desire to protect by Letters Patent is:

1. The process which comprises extracting a solution of impure wood rosin in a volatile parafiin hydro-carbon solvent with a selective solvent which exerts a selective solvent action upon the color bodies contained in said rosin and which is capable of substantial immiscihility with said parafiln hydrocarbon solvent, separating the selective solvent extract phase containing color bodies from the paraffin hydrocarbon solvent phase containing pale rosin, extracting said selective solvent phase with a volatile paraflin hydrocarbon solvent in an amount sufficient to dissolve a substantial proportion of the components of said phase which are soluble in paraffin hydrocarbons, separating the resulting paraffin hydrocarbon phase from the selective solvent phase, recycling the separated paraflin hydrocarbon phase as solution of impure rosin in the initial step of the process, and resolving theextracted selective solvent phase into a resinous residue and selective solvent.

2. The process which comprises extracting a solution of impure wood rosin in a light petroleum distillate with a selective solvent which exerts a selective solvent action upon the color bodies contained in said rosin and which is capable of substantial immiscibility with said petroleum distillate, separating the selective solvent extract phase containing color bodies from the organic phase containing pale rosin, extracting said separated selective solvent phase with a light petroleum distillate in amount suiiicient to dissolve a substantial proportion of the components of said color bodies which are soluble in petroleum hydrocarbons, separating the resulting petroleum distillate phase from the resulting selective solvent phase, re-cycling said resulting petroleum distillate phase by blending it with additional solution of impure wood rosin to be treated, treating the recycled phase and additional solution according to the process, evaporating the last-mentioned resulting selective solvent phase to recover selective solvent and a resinous residue of increased insolubility in petroleum hydrocarbons and re-cycling the selective solvent so recovered and employing it for carrying out said initial extracting step.

3. The process which comprises extracting a solution of impure wood rosin in gasoline with furfural, separating the furfural phase containing color bodies from the gasoline phase containing pale rosin, extracting the furfural phase with gasoline in amount sufiicient to dissolve a substantial proportion of the components thereof which are soluble in petroleum hydrocarbons, separating the resulting gasoline phase from the resulting furfural phase, re-cycling the resulting gasoline phase by blending it with additional solution of impure wood rosin to be treated, treating the recycled phase and additional solution according to the process, evaporating the lastmentioned resulting furfural phase to recover furfural and a resinous residue of increased insolubility in petroleum hydrocarbons, and recycling the furfural so recovered and employing it for carrying out said initial extracting step.

4. The process which comprises extracting a solution of impure wood rosin in gasoline with furfural, separating the furiural phase containing color bodies from the gasoline phase containing pale rosin, evaporating said gasoline phase to recover gasoline and a residue of pale rosin, extracting the furfural phase with gasoline at least partially embodying said recovered gasoline, separating the resulting gasoline phase from the resulting furfural phase, re-cycling the resulting gasoline phase by blending it with additional solution of impure Wood rosin to be treated, treating the recycled phase and additional solution according to the process, evaporating the last-mentioned resulting furfural phase to recover furfural and a resinous residue substantially insoluble in petroleum hydrocarbons, and re-cycling the furfural so recovered and employing it for carrying out said initial extracting step.

5. The process Which comprises extracting a solution of impure wood rosin in a volatile paraffin hydrocarbon solvent with a selective solvent which exerts a selective solvent action upon the color bodies contained in said rosin and which is capable of substantial immiscibility with said parafiin hydrocarbon solvent, separating the selective solvent extract phase containing color bodies from the paraifin hydrocarbon solvent phase containing pale rosin, countercurrently extracting said selective solvent phase with a volatile paraflin hydrocarbon solvent in an amount sufiicient to dissolve a substantial proportion of the components of said phase which are soluble in paraffin hydrocarbons, separating the resulting paraffin hydrocarbon phase from the selective solvent phase, recycling the separated paraflin hydrocarbon phase as solution of impure rosin in the initial step of the process, and resolving the extracted selective solvent phase into a resinous residue and selective solvent.

JAMES L. JONES.

CERTIFI GATE OF C ORRECTI ON Patent No. 2,556,5li 6. 7 December 11+, 19L .5.

JAMES L. JONES.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page i sec- 0nd column, line 17, after the words and period "selective solvent." insert the following claim 6. The process which comprises extracting a solution of impure wood rosin in gasoline with furfural, separating the furfural phase containing color bodies from the gasoline phase containing pale rosin, evaporating said gasoline phase to recover gasoline and a residue of pale rosin,countercurrently v extracting the furiural phase with gasoline at least partially embodying said recovered gasoline, separating the resulting gasoline phase from the resulting furfural phase, recycling the resulting gasoline phaselby blending it with additional solution of impure wood rosin to be treated, treating the recycled phase and additional solution accoding to the process, evaporating the last-mentioned resulting furfural phase to recover furfuraland a resinous residue substantially insoluble in petroleum hydrocarbons, and recycling the furfural so recovered and employing it for carrying out said initial extracting step.--;

and th t th id tt t t should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 29th day of February, A. D. 19%.

Leslie Frazer (Seal) Acting Commissioner of Patents. 

